Displaying in Multimedia In this unit you will: Identify the hardware used to display multimedia. Investigate the software used to create multimedia

Screens Cathode-ray tube (CRT) display The CRT produce images by firing a electron beam onto a phosphorescent surface. It uses a raster scan to produce an image on a screen. To maintain an image on a screen it uses a process called refreshing- a repeated raster scan.

The CRT screen A:CathodeD: Phosphor coated screen B: Conductive coatingE: Electron beam C: AnodeF: Shadow mask

Raster scan Beams fade so they must be reactivated. It is done by repeated scans of each line. This resembles a series of zig-zag lines on the screen. A complete sweep is called a field. The screen is redrawn at time/sec. This is known as the refresh rate.

The Vector display system A special type of CRT- only displays vector graphics. Directs the electron stream to draw only lines. Shading drawn as a series of lines. Have faster refresh rate than CRT using raster scan.

Liquid crystal displays LCD’s uses a piece of liquid crystal material placed between a pair of transparent electrodes. LCD’s offer considerable savings in size, weight and power.

LCD’s are very light take up less room, produces no heat, have no glare and produces no radiation. LCD’s uses less power than CRT’s. Can be powered by batteries. LCD does not produce the same picture quality as CRT. LCD’s are used in portable computers. Can be mounted on the wall. LCD’s and CRT’s

The Plasma screen Plasma display illuminates tiny coloured fluorescent lights to form an image. Each pixel is made up of three fluorescent lights - a red, a green and a blue light. The plasma display varies the intensities of the different lights to produce a full range of colours.

Touch screens Touch screens enter data by detecting the touch of the user’s finger. The user’s finger interrupts a matrix of infrared light beams. Touch screens do not allow fine precision of input. Uses big buttons or areas on screen

Projection devices A data projection panel is used with a overhead projector to project an image onto a wall or white screen. Data projectors takes a signal directly from a computer and project it onto a wall or screen.

Speakers and sound systems Speakers produce analog sound from audio digitised signals from the computer. You need software driver, sound card and a digital audio circuit board (Sound Blaster). Sound cards in PC’s can also play and create MIDI and waveform files.

Head-up displays Head-up displays are worn on the head to give the wearer a 3D image in an artificial world. It will further blur the line between what's real and what's computer-generated by enhancing what we see, hear, feel and smell.

Software Presentation software Presentation software Application software Application software Authoring software Authoring software Animation software Animation software Web browsers Web browsers HTML editors HTML editors

Presentation software Used to make a professional presentation to a group of people. Improves communication. Consists of slides. (text, graphics, animation, audio and video) Microsoft PowerPoint and AppleWorks. Include a range of options or documents: –On-screen presentations –Audience handouts –Overhead transparencies –Speaker’s notes

Application software Application software is used for a specific task. Word processors Spreadsheets Graphics software Audio software Video software Project management software

Authoring software Authoring software is used to combine the separate media types into a multimedia product. The user can sequence and time the occurrence of events. Allows for interactivity. Examples of authoring software: – Macromedia Director – HyperCard – HyperStudio

Animation software Takes individual images and creates the illusion of movement. Takes individual images and creates the illusion of movement. Types of animation software: – 2D two-dimensional – 3D three dimensional – Warping and Morphing

Web browsers A web browser is a software program that allows access to the Web. Multimedia files are embedded. Multimedia files takes longer to download. Web browsers can play audio and video with plug-ins. Examples: – Netscape Navigator – Microsoft Internet Explorer – Firefox – Safari

HTML editors HTML editors are programs to assist in creating Web pages. ( Hypertext markup language) Use tags that indicate how parts of a document will be displayed. and HTML editor is a program that specialises in writing HTML code. Tags are metadata, or information about data. JavaScript allows for more multimedia elements to be embedded in a web page.

The End Displaying in Multimedia Systems